Biopterins

Biopterins and especially tetrahydrobiopterin (BH4) are human endogenous cofactors for aromatic amino acid hydroxylases enzymes, which are involved in the metabolism of phenylalanine, the biosynthesis of nitric oxide and the biosynthesis of various neurotransmitters including dopamine, norepinephrine, epinephrine, and serotonin. BH4 is produced via de-novo, alternate and salvage pathways.